Guidewire

ABSTRACT

A guidewire includes a wire body having a first wire arranged on a distal end side and a second wire arranged on a proximal end side of the first wire. A proximal end surface of the first wire and a distal end surface of the second wire are joined to each other to form a joint portion. An outer member is arranged on an outer peripheral side of the wire body and forms a tubular shape which covers the wire body at least from a distal end portion of the first wire to the joint portion. An inner member is arranged between an outer peripheral portion of the wire body and an inner peripheral portion of the outer member and covers the joint portion. The inner member is an inner coil formed by winding a wire for the inner member into a coil shape.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/JP2012/078950 filed on Nov. 8, 2012 and claims priority to JapaneseApplication No. 2012-060597 filed on Mar. 16, 2012, the entire contentof both of which is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a guidewire.

BACKGROUND DISCUSSION

A guidewire is used to guide a catheter in a medical treatment to a sitehaving a surgical difficulty, or a medical treatment aiming to minimizeinjury to a human body, such as percutaneous transluminal coronaryangioplasty (PTCA), for example, and a medical examination such ascardiovascular radiography. The guidewire used for PTCA is inserted intothe vicinity of an angiostenosis portion, which is the target site,together with a balloon catheter in a state where a distal end of theguidewire is protruded from a distal end of the balloon catheter. Theguidewire guides a distal end portion of the balloon catheter to thevicinity of the angiostenosis portion.

In percutaneous transluminal angioplasty (PTA), which is substantiallysimilar to PTCA, the distal end portion of the balloon catheter isguided to the vicinity of the angiostenosis portion by using theguidewire to open a stenosis portion (closed portion) formed in aperipheral blood vessel such as femoral, iliac, renal, and shunt bloodvessels.

The blood vessels to which these medical treatment methods are appliedare intricately curved. Therefore, the guidewire used when the ballooncatheter is inserted into the blood vessel requires flexibility andresilience for moderate bending, pushing performance and torquetransmission performance (these are generically referred to as“operability”) for transmitting an operation in a proximal end portionto a distal end thereof, and also kink resistance (bending resistance).

Known guidewires have a first wire made of a Ni—Ti-based alloy and asecond wire made of stainless steel (for example, refer toJP-A-2008-161589). In the guidewire disclosed in JP-A-2008-161589, aguidewire is provided in which a proximal end surface of the first wireand a proximal end surface of the second wire are joined to each otherto form a joint portion, and the joint portion is covered with a coilfrom an outer peripheral side thereof. When this guidewire is used,there is a possibility that the following situations may occur dependingon the magnitude of an operator's operating force.

For example, the first wire and the second wire have considerablydifferent rigidity. Consequently, there is a possibility that the wiresin the joint portion are unintentionally bent or, on the other hand, thejoint portion is caused to have a rigidity much stronger than that ofthe leading and trailing portions thereof, and thus the joint portion isunlikely to be curved along the curves of the blood vessel.

In addition, in the guidewire disclosed in JP-A-2008-161589, a guidewireis also disclosed in which a proximal end portion of the first wire anda proximal end portion of the second wire are connected to each othervia a pipe. When this guidewire is used, depending on the magnitude ofthe operator's operating force, there is a possibility that the rigidityof a portion between the first wire and the second wire becomes verystrong in the pipe, and thus the guidewire is unlikely to be curved.

SUMMARY

The disclosure here provides a guidewire having excellent operability.

More particularly, an exemplary embodiment of the disclosure provides aguidewire including a wire body that has a first wire which is arrangedon a distal end side and a second wire which is arranged on a proximalend side of the first wire and is formed of a material whose rigidity ishigher than that of a material of the first wire, and in which aproximal end surface of the first wire and a distal end surface of thesecond wire are joined to each other so as to form a joint portion. Anouter member is arranged on an outer peripheral side of the wire bodyand forms a tubular shape which covers the wire body at least from adistal end portion of the first wire to the joint portion, and hasflexibility. An inner member is arranged between an outer peripheralportion of the wire body and an inner peripheral portion of the outermember, and covers the joint portion. The inner member is an inner coilformed by winding a wire for the inner member into a coil shape.

In addition, in the guidewire of an exemplary embodiment of thedisclosure, it is preferable that the inner coil has a distal endportion and a proximal end portion, and at least any one of these isstretchable.

In addition, it is preferable that the joint portion has an outerdiameter which is the same as an outer diameter of a proximal end of thefirst wire on a distal end side and an outer diameter of a distal end ofthe second wire on a proximal end side, respectively, and that an innerdiameter of the inner coil is larger than an outer diameter of the jointportion.

Further, in the guidewire of an exemplary embodiment of the disclosure,it is preferable that a horizontal cross-sectional shape of the wire forthe inner member has a circular shape or a flat shape.

Still further, it is preferable that the outer member is configured tohave a first outer coil which is located on a distal end side and isformed by winding a wire for a first outer member into a coil shape anda second outer coil which is connected to a proximal end side of thefirst outer coil and is formed by winding a wire for a second outermember into a coil shape, and that the wire for the inner member is thethinnest wire among the wire for the first outer member, the wire forthe second outer member, and the wire for the inner member.

A guidewire according to a further exemplary embodiment of thedisclosure includes a wire body that has a first wire which is arrangedon a distal end side and a second wire which is arranged on a proximalend side of the first wire and is formed of a material whose rigidity ishigher than that of a material of the first wire, and in which aproximal end surface of the first wire and a distal end surface of thesecond wire are joined to each other so as to form a joint portion. Anouter member is arranged on an outer peripheral side of the wire bodyand forms a tubular shape which covers the wire body at least from adistal end portion of the first wire to the joint portion, and hasflexibility. An inner member is arranged between an outer peripheralportion of the wire body and an inner peripheral portion of the outermember, and covers the joint portion. The inner member has a tubularshape and has multiple penetrating holes which penetrate a tube wallthereof.

In addition, it is preferable that the respective penetrating holes arerespectively formed along a circumferential direction of the innermember.

Further, in the guidewire according to an exemplary embodiment of thedisclosure, it is preferable that the inner member has a function ofrelieving stress generated in the joint portion in a state where theguidewire is used.

It is also preferable that the first outer coil has a gap between theadjacent wires for the first outer member, that in the second outercoil, the adjacent wires for the second outer member are in contact witheach other, and that in the inner coil, the adjacent wires for the innermember are apart from each other.

Still further, it is preferable that winding directions of the wire forthe first outer member, the wire for the second outer member, and thewire for the inner member are the same as one another.

In addition, in the guidewire according to an exemplary embodiment ofthe disclosure, it is preferable that the winding directions of the wirefor the first outer member and the wire for the second outer member arethe same as each other, and the winding direction of the wire for theinner member is opposite to the winding directions of the wire for thefirst outer member and the wire for the second outer member.

Further, it is preferable that the inner peripheral portion of the innermember is apart from the outer peripheral portion of the wire body.

Still further, it is preferable that the outer peripheral portion of theinner member is apart from the inner peripheral portion of the outermember.

Also, in the guidewire according to an exemplary embodiment of thedisclosure, it is preferable that in the inner member, at least any onebetween the distal end portion and the proximal end portion thereof issupported with respect to the wire body.

In addition, it is preferable that the guidewire includes a fixingmember which fixes a longitudinally intermediate portion of the outermember to the first wire.

Further, it is preferable that the fixing member also fixes the innermember to the wire body.

In addition, in the guidewire according to an exemplary embodiment ofthe disclosure, it is preferable that the inner member is extended sothat the distal end portion thereof protrudes from the fixing member ina direction toward the distal end.

Further, it is preferable that the outer member is configured to havethe first outer coil which is located on the distal end side and has acoil shape, and the second outer coil which is connected to the proximalend side of the first outer coil and has a coil shape.

Still further, it is preferable that the inner member is more flexiblethan the first outer coil.

Also, it is preferable that a material of the first outer coil and amaterial of the second outer coil are different from each other.

In addition, it is preferable that a material of the first outer coiland a material of the inner member are the same as each other.

In addition, in the guidewire according to an exemplary embodiment ofthe disclosure, it is preferable that the proximal end portion of thefirst wire has a first wire side constant outer diameter portion whoseouter diameter is constant, that the distal end portion of the secondwire has a second wire side constant outer diameter portion whose outerdiameter is constant, and that the outer diameter of the first wire sideconstant outer diameter portion and the outer diameter of the secondwire side constant outer diameter portion are the same as each other.

In addition, it is preferable that the first wire has a first wire sidetapered portion whose outer diameter gradually decreases in a directiontoward the distal end, on the distal end side of the first wire sideconstant outer diameter portion.

Further, it is preferable that the second wire has a second wire sidetapered portion whose outer diameter gradually increases in a directiontoward the proximal end, on the proximal end side of the second wireside constant outer diameter portion.

When a guidewire is being used, a torque acting around an axis thereof,a pushing force acting from a proximal end side thereof, and a pressingforce acting from a curved blood vessel (force which bends theguidewire) are applied to the guidewire. In this case, stress isgenerated in a joined portion formed by a first wire and a second wirebeing joined to each other. However, according to an exemplaryembodiment of the disclosure, the stress is reliably relieved by aninner member. This can reliably prevent a problem in which the guidewireis unintentionally bent in the joint portion or is broken in the jointportion, while the guidewire is used (operated). Accordingly, theguidewire exhibits excellent torque transmission performance, pushingperformance, and kink resistance, for example.

In addition, according to the disclosure herein, the inner member allowssmooth transition of rigidity from the second wire to the first wire.This enables the guidewire to be smoothly curved even near the jointportion when the guidewire is inserted into the curved blood vessel,thereby improving an ability to follow the blood vessel. That is, theoperability of the guidewire is improved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a longitudinal cross-sectional view illustrating a firstexemplary embodiment of a guidewire according to the disclosure.

FIG. 2 is a longitudinal cross-sectional view illustrating a secondexemplary embodiment of a guidewire according to the disclosure.

FIG. 3 is a longitudinal cross-sectional view illustrating a thirdexemplary embodiment of a guidewire according to the disclosure.

FIG. 4 is a longitudinal cross-sectional view illustrating a fourthexemplary embodiment of a guidewire according to the disclosure.

FIG. 5 is a longitudinal cross-sectional view illustrating a fifthexemplary embodiment of a guidewire according to the disclosure.

FIG. 6 is an enlarged longitudinal cross-sectional view of an innermember included in a guidewire (sixth exemplary embodiment) according tothe disclosure.

FIG. 7 is an enlarged longitudinal cross-sectional view of an innermember included in a guidewire (seventh exemplary embodiment) accordingto the disclosure.

FIG. 8 is an enlarged longitudinal cross-sectional view of an innermember included in a guidewire (eighth exemplary embodiment) accordingto the disclosure.

FIG. 9 is a longitudinal cross-sectional view illustrating a ninthexemplary embodiment of a guidewire according to the disclosure.

FIG. 10 is a side view of an inner member included in the guidewireillustrated in FIG. 9.

DETAILED DESCRIPTION

Hereinafter, a guidewire according to the disclosure herein will bedescribed in detail with reference to preferred exemplary embodimentsillustrated in the accompanying drawings.

FIG. 1 is a longitudinal cross-sectional view illustrating a firstexemplary embodiment of a guidewire according to the disclosure herein.For convenience of description, the right side in FIG. 1 (FIGS. 2 to 10are also the same) is referred to as a “proximal end”, the left side isreferred to as a “distal end”. In addition, in FIG. 1 (FIGS. 2 to 10 arealso the same), in order to facilitate understanding, the guidewire isschematically illustrated by shortening a longitudinal direction of theguidewire and by exaggeratingly widening a thickness direction of theguidewire. Accordingly, the illustrated ratio between the longitudinaldirection and the thickness direction is different from an actual ratio.

A guidewire 1 illustrated in FIG. 1 is a guidewire used to guide acatheter (balloon catheter) in a medical treatment to a site having asurgical difficulty, such as percutaneous transluminal coronaryangioplasty (PTCA), for example. In PTCA, the guidewire 1 is insertedinto the vicinity of an angiostenosis portion, which is the target site,together with the catheter in a state where a distal end of theguidewire 1 is protruded from a distal end of the catheter. Theguidewire 1 guides a distal end portion of the catheter to the vicinityof the angiostenosis portion. Note that, although not particularlylimited, it is preferable that the overall length of the guidewire 1 is200 mm to 5,000 mm.

The guidewire 1 includes a wire body 10, an outer member 5 which isarranged on an outer peripheral side of the wire body 10, and an innermember 4A which is arranged between an outer peripheral portion of thewire body 10 and an inner peripheral portion of the outer member 5.Hereinafter, a configuration of each portion will be described ingreater detail.

The wire body 10 has a first wire 2 which is arranged on a distal endside and a second wire 3 which is arranged adjacent to a proximal endside of the first wire 2, and is formed by joining (connecting) thefirst wire 2 and the second wire 3 to each other.

The first wire 2 is composed of a wire rod having flexibility and/orelasticity. A preferable material for the wire rod (first wire 2)includes a Ni—Ti-based alloy such as Ni—Ti alloys of Ni of 49 atomic %to 52 atomic %, for example. The Ni—Ti-based alloy is relativelyflexible, has resilience, and is unlikely to have a bending tendency.Therefore, if the first wire 2 is formed of the Ni—Ti-based alloy, inthe guidewire 1, a portion on the distal end side can obtain sufficientflexibility and resilience against bending. An ability to follow thecomplicated curved and bent blood vessel is improved and excellentoperability can be obtained. Even when the first wire 2 is deformed bybeing repeatedly curved and bent, the resilience provided for the firstwire 2 does not increase the bending tendency thereof. Accordingly,while the guidewire 1 is used, it is possible to prevent the operabilityfrom being degraded due to the bending tendency occurring in the firstwire 2.

The Ni—Ti alloy having the above-described composition may also havesuper-elasticity through heat treatment or the like. However, even thosewhich contain Ni of more than 52 atomic % and do not substantially showsuper-elasticity can be used, as long as they have moderate flexibilityand elasticity.

The first wire 2 is configured so that a flat plate portion 21, a firstconstant outer diameter portion 22, a tapered portion (first wire sidetapered portion) 23, and a second constant outer diameter portion (firstwire side constant outer diameter portion) 24 are formed sequentiallyfrom the distal end side.

The flat plate portion 21 is a portion which has a plate shape (i.e.,planar or ribbon shape), and in which a thickness and a width areconstant in the longitudinal direction of the wire. This flat plateportion 21 can be used by being deformed (reshaped: newly shaped) into adesired shape. In general, a doctor sometimes uses the guidewire 1 bydeforming the distal end portion of the guidewire into a desired shapein advance, so that the distal end portion of the guiding catheter orthe like corresponds to a shape of the blood vessel, or so that thedistal end portion is smoothly guided by properly selecting a course ata diverging point of the blood vessel. Bending the distal end portion ofthe guidewire 1 into a desired shape as described above is calledreshaping. Providing the flat plate portion 21 on the guidewire 1facilitates the reshaping and enables the reshaping to be reliablyperformed, thereby significantly improving the operability when theguidewire 1 is inserted into the blood vessel.

The first constant outer diameter portion 22 is a portion whose outerdiameter is constant along the longitudinal direction of the wire. It ispreferable that the outer diameter of the first constant outer diameterportion 22 is larger than the thickness of the flat plate portion 21 andis smaller than the width of the flat plate portion 21.

The tapered portion 23 is a portion whose outer diameter graduallydecreases in a direction toward the distal end. Since the first wire 2has the tapered portion 23, it is possible to gradually decrease therigidity (flexural rigidity and torsional rigidity) of the first wire 2in the direction toward the distal end. As a result, the guidewire 1obtains excellent flexibility in the distal end portion thereof, therebyimproving the ability to follow the blood vessel or the like and safety.Furthermore, it is possible to prevent bending. Note that, the outerdiameter of the distal end of the tapered portion 23 is preferably thesame as the outer diameter of the first constant outer diameter portion22. In addition, a taper angle (decreasing rate of the outer diameter)of the tapered portion 23 may be constant along the longitudinaldirection of the wire, or the tapered portion 23 may have a portionwhich varies along the longitudinal direction of the wire. For example,a portion having a relatively large taper angle (decreasing rate of theouter diameter) and a portion having a relatively small taper angle maybe alternately and repeatedly formed multiple times.

The second constant outer diameter portion 24 is a portion whose outerdiameter is constant in the longitudinal direction of the wire. Theouter diameter of the second constant outer diameter portion 24 issubstantially the same as the outer diameter of the proximal end of thetapered portion 23.

The distal end (distal end surface 311) of the second wire 3 isconnected to the proximal end (proximal end surface 241) of the firstwire 2 by welding, for example. The second wire 3 has a flexibility andelasticity similar to the first wire 2, and is composed of a wire rodhaving a rigidity which is higher than that of the material (Ni—Ti-basedalloy) of the first wire 2. A suitable material of this wire rod (secondwire 3) is not particularly limited, but includes various metallicmaterials such as stainless steel and a cobalt-based alloy, for example.

For example, the stainless steel includes all SUS product types such asSUS304, SUS303, SUS316, SUS316L, SUS316J1, SUS316J1L, SUS405, SUS430,SUS434, SUS444, SUS429, SUS430F, SUS302, and the like.

In addition, any cobalt-based alloy may be used as long as thecobalt-based alloy contains Co as a constituting element. However, it ispreferable to use a cobalt-based alloy which contains Co as a maincomponent (Co-based alloy: alloy in which a content of Co is highest ina weight ratio within all elements constituting the alloy). It is morepreferable to use a Co—Ni—Cr-based alloy. The cobalt-based alloy has ahigh elastic modulus when used in the wire, and has a moderate elasticlimit. Therefore, the second wire 3 formed of the cobalt-based alloy hasexcellent torque transmission performance, and is very unlikely tosuffer from a problem of buckling. In addition, the cobalt-based alloyhas a high elastic modulus, and is cold-formable even with a highelastic limit. Since the cobalt-based alloy has a high elastic limit, itis possible to sufficiently prevent the occurrence of buckling, todecrease the diameter, and to provide the wire with sufficientflexibility and rigidity so as to be inserted into a predetermined site.

As the Co—Ni—Cr-based alloy, for example, it is preferable to use analloy having a composition of Co of 28 wt % to 50 wt %-Ni of 10 wt % to30 wt %-Cr of 10 wt % to 30 wt %-Fe for the remaining portion, or analloy in which a portion thereof is substituted by other elements(substituting element). Allowing the alloy to contain the substitutingelements demonstrates an inherent advantageous effect depending on thesubstituted element. For example, it is possible to obtain furtherimproved strength of the second wire 3 by containing at least one typeselected from Ti, Nb, Ta, Be, and Mo as the substituting element. Notethat, in a case of containing elements other than Co, Ni, and Cr, it ispreferable that the content thereof (of the whole substituting elements)is 30 wt % or less.

In addition, a portion of Co, Ni, and Cr may be substituted by otherelements. For example, a portion of Ni may be substituted by Mn.Accordingly, this can achieve further improved workability, for example.In addition, a portion of Cr may be substituted by Mo and/or W. This canachieve a further improved elastic limit. Out of the Co—Ni—Cr-basedalloys, it is particularly preferable to use a Co—Ni—Cr—Mo-based alloywhich contains Mo.

The second wire 3 is configured so that a first constant outer diameterportion (second wire side constant outer diameter portion) 31, a firsttapered portion (second wire side tapered portion) 32, a second constantouter diameter portion 33, a second tapered portion 34, and a thirdconstant outer diameter portion 35 are formed sequentially from thedistal end side.

The first constant outer diameter portion 31 is a portion whose outerdiameter is constant along the longitudinal direction of the wire. Theouter diameter of the first constant outer diameter portion 31 issubstantially the same as the outer diameter of the second constantouter diameter portion of the first wire 2.

The first tapered portion 32 is a portion whose outer diameter graduallyincreases in a direction toward the proximal end.

The second constant outer diameter portion 33 is a portion whose outerdiameter is constant along the longitudinal direction of the wire.

The second tapered portion 34 is a portion whose outer diametergradually increases in a direction toward the proximal end.

In combination, the first constant outer diameter portion 31, the firsttapered portion 32, the second constant outer diameter portion 33, andthe second tapered portion 34 allow physical characteristics of theguidewire 1, particularly the elasticity, to be smoothly changed fromthe second wire 3 to the first wire 2.

The third constant outer diameter portion 35 is a portion whose outerdiameter is constant along the longitudinal direction of the wire. Thethird constant outer diameter portion 35 functions as a grip portionwhich is gripped by a user to operate the guidewire 1. It is preferablethat a proximal end surface 351 of the third constant outer diameterportion 35 has a round shape.

In the exemplary embodiment, a resin coating layer 8 which covers anouter peripheral surface of the second wire 3 is preferably disposed onthe second wire 3 from the second tapered portion 34 to the thirdconstant outer diameter portion 35. This resin coating layer 8 may beformed for various purposes, but as an example, it is useful forimproving the operability for the guidewire 1 by reducing friction(sliding resistance) of the guidewire 1 and thereby improving slidingperformance.

In order to reduce the friction (sliding resistance) of the guidewire 1,it is preferable that the resin coating layer 8 is formed of a materialwhich can reduce the friction as described below. In this manner,frictional resistance (sliding resistance) between the guidewire 1 andthe inner wall of the catheter used together with the guidewire 1 isreduced and the sliding performance is improved. Accordingly, theoperability of the guidewire 1 inside the catheter increases. Inaddition, since the sliding resistance of the guidewire 1 is reduced,when the guidewire 1 is moved and/or rotated inside the catheter, it ispossible to more reliably prevent kinks (bending) or torsion of theguidewire 1, particularly kinks or torsion near the joint portion 14.

For example, a material which can reduce this friction includes apolyolefin such as polyethylene and polypropylene, polyvinyl chloride,polyesters (PET, PBT, and the like), polyamides, polyimides,polyurethane, polystyrene, polycarbonate, silicone resins, and fluorineresins (PTFE, ETFE, and the like), or a composite material of these.

In addition, in some cases, the resin coating layer 8 may be providedfor the purpose of improving safety when the guidewire 1 is insertedinto the blood vessel. For this purpose, it is preferable that the resincoating layer 8 is formed of a material having sufficient flexibility(soft material, elastic material).

For example, a material having sufficient flexibility includes apolyolefin such as polyethylene and polypropylene, polyvinyl chloride,polyesters (PET, PBT, and the like), polyamides, polyimides,polyurethane, polystyrene, silicone resins, thermoplastic elastomerssuch as polyurethane elastomers, polyester elastomers, and polyamideelastomers, and various rubber materials such as latex rubber andsilicone rubber, or a composite material in which two or more out ofthese are combined.

Note that, the resin coating layer 8 may have a single layer or may be astacked body having two or more layers.

In addition, it is preferable that at least the distal end portion ofthe guidewire 1 is coated with a hydrophilic material. It is preferablethat the guidewire 1 includes a layer formed of the hydrophilic materialon an outer surface of the outer member 5 (to be described later). Thiscauses the hydrophilic material to be wetted, thereby allowinglubrication performance such that the friction (sliding resistance) ofthe guidewire 1 is reduced, the sliding performance is improved, and theoperability of the guidewire 1 is thereby improved.

By way of example, the hydrophilic material may include cellulose-basedpolymeric materials, polyethylene oxide-based polymeric materials,maleic anhydride-based polymeric substances (for example, maleicanhydride copolymers such as methyl vinyl ether-maleic anhydridecopolymers), acrylamide-based polymeric materials (for example, blockcopolymers of polyacrylamide, polyglycidyl methacrylate-dimethylacrylamide (PGMA-DMAA)), water-soluble nylon, polyvinyl alcohol,polyvinyl pyrrolidone, and the like.

In many cases, this hydrophilic material is wetted (absorbs water) todemonstrate the lubrication performance, and reduces the frictionalresistance (sliding resistance) between the guidewire 1 and the innerwall of the catheter used together with the guidewire 1. This improvesthe sliding performance of the guidewire 1, thereby further improvingthe operability of the guidewire 1 inside the catheter.

In addition, in the guidewire 1, an average outer diameter of the firstwire 2 is smaller than an average outer diameter of the second wire 3.This allows the guidewire 1 to have sufficient flexibility for the firstwire 2 which forms the distal end side, and to have relatively highrigidity for the second wire 3 which forms the proximal end side.Therefore, it is possible to concurrently obtain flexibility of thedistal end portion and excellent operability (pushing performance,torque transmission performance, and the like).

As described above, in the wire body 10, the proximal end surface 241 ofthe first wire 2 and the distal end surface 311 of the second wire 3 arejoined to each other by welding. In this manner, in the wire body 10,the joint portion 14 is formed in an intermediate portion in thelongitudinal direction of the wire.

The joint portion 14 can obtain relatively strong joint strength sincethe joint portion 14 is a portion formed by welding. A welding methodfor the first wire 2 and the second wire 3 is not particularly limited.For example, the welding method may include friction welding, spotwelding using a laser, and butt resistance welding such as upsetwelding. However, it is particularly preferable to use butt resistancewelding since the butt resistance welding is relatively simple and canobtain the high joint strength.

The joint portion 14 may be a portion which is joined by a brazingmaterial. It is preferable that the proximal end surface 241 of thefirst wire 2 and the distal end surface 311 of the second wire 3 arejoined to each other via the brazing material. It is preferable that theouter diameter including the brazing material portion is substantiallythe same as the second constant outer diameter portion 24 of the firstwire 2 and the first constant outer diameter portion 31 of the secondwire 3.

In addition, the joint portion 14 may be configured so that the proximalend surface 241 of the first wire 2 and the distal end surface 311 ofthe second wire 3 are joined to each other via an intermediate member.It is preferable that the intermediate member includes a distal endportion and a proximal end portion, and that the distal end portion ofthe intermediate member is welded to the proximal end surface 241 of thefirst wire 2, and the proximal end portion of the intermediate member iswelded to the distal end surface 311 of the second wire 3. It ispreferable that the outer diameter of the intermediate member is thesame as the outer diameters of the second constant outer diameterportion 24 of the first wire 2 and the first constant outer diameterportion 31 of the second wire 3.

In addition, in the joint portion 14, the outer diameter thereof is thesame as the outer diameter of the constant outer diameter portion 24 ofthe first wire 2 on the distal end side and the outer diameter of theconstant outer diameter portion 31 of the second wire 3 on the proximalend side, respectively. This can sufficiently ensure the flexibilitynear the joint portion 14 or the resilience against bending, and at thesame time, it is possible to maintain the strength of each wire and thejoint portion 14.

In the wire body 10, a distal end side portion thereof is inserted intothe outer member 5 having a tubular shape as a whole in a non-contactmanner, in a natural state where an external force is not applied. Inthis manner, in the wire body 10, a section from the intermediateportion (distal end portion) of the flat plate portion 21 of the firstwire 2, via the joint portion 14, to the intermediate portion of thesecond constant outer diameter portion 33 of the second wire 3 on theproximal end side which is located farther from the joint portion 14 isin a state of being covered with the outer member 5. The length of theouter member 5 is not limited as long as the outer member 5 covers atleast a section from the distal end portion of the first wire 2 to thejoint portion 14 of the wire body 10.

The outer member 5 has a tubular shape as a whole. In the exemplaryconfiguration illustrated in FIG. 1, the outer member 5 is configured tohave a first outer coil 51 which is located on the distal end side and asecond outer coil 52 which is connected to the proximal end side of thefirst outer coil 51.

The first outer coil 51 is formed by winding a first wire (wire for thefirst outer member) 511 into a coil shape (spiral shape). In the firstouter coil 51, the adjacent first wires 511 have a gap therebetween in anatural state where the external force is not applied, and accordinglyare coarsely wound.

The second outer coil 52 is formed by winding a second wire (wire forthe second outer member) 521 into a coil shape in a direction which isthe same as that of the first outer coil 51. In the second outer coil52, the adjacent second wires 521 are in contact with each other in thenatural state, and accordingly are densely wound.

In addition, the overall length (length in the longitudinal direction ofthe wire) of the first outer coil 51 is shorter than the overall length(length in the longitudinal direction of the wire) of the second outercoil 52. This enables the first outer coil 51 to cover a section fromthe intermediate portion of the flat plate portion 21 of the first wire2 to the vicinity of a boundary portion between the tapered portion 23and the second constant outer diameter portion 24. In addition, thesecond outer coil 52 can cover a section from the vicinity of theboundary portion to the intermediate portion of the second constantouter diameter portion 33 of the second wire 3.

With the outer member 5 having the above-described configuration, thedistal end side portion of the wire body 10 is covered with the outermember 5. Thus, it is possible to minimize an area in contact with theblood vessel wall. Accordingly, sliding resistance is reduced, and theoperability of the guidewire 1 is further improved.

The inner diameter of the first outer coil 51 is preferably smaller thanthe inner diameter of the second outer coil 52.

The outer diameter of the first outer coil 51 and the outer diameter ofthe second outer coil 52 are each constant along the longitudinaldirection of the wire, and are preferably the same as each other.

The diameter of the first wire 511 is larger than the diameter of thesecond wire 521.

The constituting material of the first wire 511 (first outer coil 51)may be the same as the constituting material of the second wire 521(second outer coil 52). However, it is preferable that these materialsare different from each other. When the constituting material of thefirst wire 511 and the constituting material of the second wire 521 aredifferent from each other, it is preferable to use a radiopaque materialas the configuring material of the first wire 511. For example, it ispossible to use Pt or an alloy thereof (for example, Pt—Ni alloy, Pt—Walloy). As the constituting material of the second wire 521, it ispreferable to use a material which is less radiopaque than the firstwire 511. For example, similar to the constituting material of thesecond wire 3, it is possible to use stainless steel. It is preferableto use the above-described materials for the first wire 511, since it ispossible to insert the guidewire 1 into a living body while checking aposition of the distal end portion of the guidewire 1 by way of X-rayfluoroscopy.

As illustrated in FIG. 1, the outer member 5 is configured so that bothend portions and the intermediate portion in the longitudinal directionare fixed to the wire body 10 respectively via the fixing materials(fixing members) 11, 12, and 13. This reliably prevents positionaldeviation of the outer member 5 in the longitudinal direction of thewire with respect to the wire body 10.

In the configuration illustrated in FIG. 1, in the first outer coil 51,the distal end portion thereof is fixed to the flat plate portion 21 ofthe wire body 10 via the fixing material 11, and the proximal endportion is fixed in the vicinity of the boundary portion between thetapered portion 23 of the wire body 10 and the second constant outerdiameter portion 24 via the fixing material 12. In addition, in thesecond outer coil 52, the distal end portion thereof is fixed in thevicinity of the boundary portion between the tapered portion 23 of thewire body 10 and the second constant outer diameter portion 24, and theproximal end portion is fixed to the second constant outer diameterportion 33 of the wire body 10. The fixing material 12 has bothfunctions of fixing the first outer coil 51 to the wire body 10 andfixing the second outer coil 52 to the wire body 10. Thus, the firstouter coil 51 and the second outer coil 52 are connected to each othervia the fixing material 12.

These fixing materials 11, 12, and 13 each are formed of solder (brazingmaterial). The fixing materials 11, 12, and 13 may also be an adhesive,without being limited to the solder. In addition, in order to preventdamage to the inner wall of the body lumen such as the blood vessel, itis preferable that a distal end surface 111 of the fixing material 11and a proximal end surface 131 of the fixing material 13 has a roundshape.

As described above, in the wire body 10, the distal end side portionthereof is inserted into the outer member 5 in a non-contact manner. Inthis manner, a gap 15 is formed between the outer peripheral portion ofthe wire body 10 and the inner peripheral portion of the outer member 5(second outer coil 52), and an inner member 4A is arranged in the gap15. The inner member 4A is an inner coil 41 (third coil) formed bywinding a wire (third wire) into a coil shape around a central axis ofthe wire body 10, and the wire body 10 is inserted into the inner sidethereof. In this manner, the inner member 4A (inner coil) cancollectively cover the joint portion 14, the second constant outerdiameter portion 24 on the distal end side of the joint portion 14, andthe first constant outer diameter portion 31 on the proximal end side.The inner diameter and the outer diameter of the inner member 4A arerespectively constant along the longitudinal direction of the wire.

In addition, in the inner member 4A, the distal end portion 42 thereofis supported by and fixed to the wire body 10, and the fixing material12 is responsible for the fixing. That is, the distal end portion 42 ofthe inner member 4A is supported by and fixed to the wire body 10 viathe fixing material 12. A proximal end portion 45 of the inner member 4Ais not fixed to the wire body 10. Furthermore, the outer diameter of thewire for the inner coil 41 of the inner member 4A is larger than that ofa gap between the wire body 10 and the inner member 4A. This causes theinner member 4A to be in a state of being cantilevered, and thus, theproximal end side portion thereof (proximal end portion 45) can bestretched in the longitudinal direction of the wire. Portions other thanthe portion fixed by the fixing material 12 in the distal end portion 42of the inner member 4A are arranged in a freely stretchable state alongthe longitudinal direction of the wire body 10.

According to this configuration, even when torque is applied to theguidewire 1 and a torsional load is also applied to the inner member 4A,the inner member 4A is stretchable in the longitudinal direction of thewire and thus, can escape the load. Accordingly, it is possible todeliberately prevent damage to the inner member 4A.

Note that, the fixing material 12 not only fixes the outer member 5 butalso fixes the inner member 4A. Accordingly, it is possible to omit amanufacturing step of separately providing a member for fixing the innermember 4A, thereby enabling the structure of the guidewire 1 to besimplified.

When the guidewire 1 is used, torque acting around the axis thereof, apushing force acting from the proximal end side, a pressing force actingfrom the curved blood vessel (force which bends the guidewire 1), andother forces are all applied to the guidewire 1. Therefore, acorresponding stress is generated in the joint portion 14. However, thestress is reliably relieved by the inner member 4A which is arranged asdescribed above. This can reliably prevent a problem in which theguidewire 1 is unintentionally bent in the joint portion 14 or is brokenin the joint portion 14 while the guidewire 1 is used (operated).Accordingly, the guidewire 1 has excellent operability, that is,excellent torque transmission performance, pushing performance, and kinkresistance.

In addition, the inner member 4A allows smooth transition of therigidity from the second wire 3 to the first wire 2. The vicinity of theproximal end portion of the first wire 2, whose rigidity is lower thanthat of the second wire 3, is likely to be largely deformed with respectto the bending stress. However, even when the vicinity of the proximalend portion of the first wire 2 which is covered with the inner member4A is bent, the inner member 4A can prevent excessivecurving-deformation. That is, an inner surface of the inner member 4A onthe outer curving side comes into contact with an outer surface of theproximal end portion of the first wire 2, thereby suppressing thebending. The wires for the inner coil 41 of the inner member 4A on theinner curving side are gathered and come into contact with each other.Accordingly, it is possible to prevent excessive bending in the proximalend portion of the first wire 2. This enables the guidewire 1 to besmoothly curved even in the vicinity of the joint portion 14 when theguidewire 1 is inserted into the curved blood vessel, thereby improvingthe operability.

As illustrated in FIG. 1, in the inner member 4A, the inner diameterthereof is larger than the outer diameter of the joint portion 14, andthe outer diameter is smaller than the inner diameter of the secondouter coil 52 (outer member 5). This causes an inner peripheral portion43 of the inner member 4A to be spaced apart from an outer peripheralportion 242 of the second constant outer diameter portion 24 of thefirst wire 2 and an outer peripheral portion 312 of the first constantouter diameter portion 31 of the second wire 3. In addition, an outerperipheral portion 44 of the inner member 4A is caused to be spacedapart from an inner peripheral portion 522 of the second outer coil 52.This separation and a synergistic effect of the stretchable inner member4A can reliably prevent a case where one wire out of the adjacent wiresfor the inner coil 41 rides on the other wire, which can occur while theguidewire 1 is used, that is, positional deviation between the wires forthe inner coil 41.

In addition, as illustrated in FIG. 1, a horizontal cross-sectionalshape of the wire for the inner coil 41 is a circular shape. Then, it ispreferable that the diameter of the wire for the inner coil 41 is thesame as or smaller than the diameter of the second wire 521 forming thesecond outer coil 52. According to this configuration, it is possible toincrease the diameter of the second wire 521 of the second outer coil 52while maintaining a minimized gap between the second outer coil 52 andthe inner member 4A. Therefore, it is possible to prevent a positionaldeviation between the second wires 521 of the second outer coil 52.Furthermore, the constituting material of the wire for the inner coil 41(inner member 4A) is the same as the constituting material of the firstwire 511 (first outer coil 51). For example, as described above,stainless steel can be used.

In addition, it is preferable to densely wind the wires for the innercoil 41 of the inner member 4A. This allows the inner member 4A to beprovided with initial tension. Power then generated by the inner member4A (i.e., when attempting to unwind) demonstrates an effect ofpreventing the wire body 10 from being curved.

Furthermore, the diameter of the wire for the inner coil 41 of the innermember 4A is larger than the diameter of the gap between the innermember 4A and the second outer coil 52. Therefore, it is possible toprevent the positional deviation between the wires for the inner coil41. In addition, the diameter of the second wire 521 of the second outercoil 52 is larger than the diameter of the gap between the inner member4A and the second outer coil 52. Therefore, it is possible to prevent apositional deviation between the second wires 521.

The inner member 4A configured with such a wire for the inner coil 41has moderate flexibility and straightness. This can more reliablyrelieve the stress generated in the joint portion 14 and reliablyprevent the inner member 4A itself from excessively interfering with thecurving when the guidewire 1 is curved.

In addition, a winding direction of the wire for the inner coil 41 isthe same as respective winding directions of the first wire 511 and thesecond wire 521. In this manner, diameter decreasing and diameterincreasing are the same as each other in each coil (first outer coil 51and second outer coil 52) with respect to the rotation direction aroundthe axis of the guidewire 1. Accordingly, there is an advantage in thatit is possible to prevent damage to each coil.

FIG. 2 is a longitudinal cross-sectional view illustrating a secondexemplary embodiment of a guidewire according to the disclosure herein.

Hereinafter, the second exemplary embodiment of the guidewire accordingto the disclosure will be described with reference to the drawing.However, points different from those in the above-described embodimentwill be mainly described, and description of the same points will beomitted.

The second exemplary embodiment is the same as the first embodimentexcept that a shape of an inner member is different.

As illustrated in FIG. 2, in the guidewire 1 of the second exemplaryembodiment, an inner member 4B is configured so that the adjacent wiresfor the inner coil 41 are spaced apart from each other in a naturalstate, and the inner member 4B is coarsely wound. This causes the innermember 4B to have initial tension which is weaker than that of thedensely wound second outer coil 52.

This coarsely wound inner member 4B becomes more likely to be stretchedin the longitudinal direction of the wire. This can more reliablyprevent a case where one wire out of the adjacent wires for the innercoil 41 rides on the other wire, which can occur while the guidewire 1is used. In addition, there is also an advantage in that it is possibleto prevent the operability from being degraded, since the providedflexibility allows a smooth change in physical properties.

FIG. 3 is a longitudinal cross-sectional view illustrating a thirdexemplary embodiment of a guidewire according to the disclosure herein.

Hereinafter, the third embodiment of the guidewire according to thedisclosure will be described with reference to the drawing. However,points different from those in the above-described embodiments will bemainly described, and description of the same points will be omitted.

The third exemplary embodiment is the same as the first embodimentexcept that a shape of an inner member is different.

As illustrated in FIG. 3, in the guidewire 1 of the third embodiment,the winding direction of the wire for the inner coil 41 forming an innermember 4C is opposite to the winding direction of a wire for the secondouter member 521 forming the second outer coil 52 (the same windingdirection is applied to a wire for the first outer member 511). Thisreliably prevents the guidewire 1 from being unintentionally deformedsince the wire for the inner coil 41 is caught in a portion between theadjacent wires for the second outer member 521 while the guidewire 1 isused.

FIG. 4 is a longitudinal cross-sectional view illustrating a fourthexemplary embodiment of a guidewire according to the disclosure herein.

Hereinafter, the fourth exemplary embodiment of the guidewire accordingto the disclosure will be described with reference to the drawing.However, points different from those in the above-described embodimentswill be mainly described, and description of the same points will beomitted.

The fourth exemplary embodiment is the same as the first embodimentexcept that a length of an inner member is different.

As illustrated in FIG. 4, in the guidewire 1 of the fourth embodiment,an inner member 4D has a protruding portion 421 which is formed by thedistal end portion 42 of the inner member 4D inserted into the fixingmaterial 12 to protrude and extend from the fixing material 12 in adirection toward the distal end. A protruding amount of the protrudingportion 421 is not particularly limited, but for example, it ispreferable that the protruding amount is 1% to 34% of the overall lengthof the inner member 4D.

The protruding portion 421 functions so as to fill a portion between thefirst outer coil 51 and the first wire 2. This can more reliably preventa case where one wire out of the adjacent first wires 511 rides on theother wire, in the proximal end portion of the first outer coil 51,which can occur while the guidewire 1 is used. Note that, this riding ismore likely to occur in the proximal end portion as compared to thedistal end portion of the coil.

FIG. 5 is a longitudinal cross-sectional view illustrating a fifthexemplary embodiment of a guidewire according to the disclosure herein.

Hereinafter, the fifth exemplary embodiment of the guidewire accordingto the disclosure will be described with reference to the drawing.However, points different from those in the above-described embodimentswill be mainly described, and description of the same points will beomitted.

The fifth exemplary embodiment is the same as the first embodimentexcept that a support location of the inner member with respect to thewire body is different.

As illustrated in FIG. 5, in the guidewire 1 of the fifth embodiment, aninner member 4E is arranged in a stretchable state from the distal endportion 42 thereof to the proximal end portion 45. More specifically, inthe inner member 4E, the distal end portion 42 thereof is spaced apartfrom the fixing material 12, and the proximal end portion 45 is locatedin the tapered portion 32 of the second wire 3. It is preferable thatthe distal end portion 42 of the inner member 4E leave a gap from thefixing material 12, whose size is equal to or smaller than that of adiameter of the wire for the inner coil 41. This can prevent damage tothe inner member 4E which may occur due to excessive loosening of thewire body 10 in an axial direction. In addition, in the proximal endportion 45 of the inner member 4E, the outer surface of the firsttapered portion 32 and the inner surface of the proximal end portion 45are in a contact state, in a location where the inner diameter of theinner member 4E reaches the outer diameter of the first tapered portion32 of the second wire 3. In this state, a movement of the inner member4E to the proximal end side of the wire body 10 is substantiallyrestricted. In this manner, the inner member 4E is in a state having nofixed point with respect to the wire body 10, and thus, the entire bodycan be stretched in the longitudinal direction of the wire. According tothis configuration, even when the torque is applied to the guidewire 1and a shaking load is also applied to the inner member 4E, the innermember 4E is stretchable in the longitudinal direction of the wire andthus, can escape the load. Accordingly, it is possible to deliberatelyprevent damage to the inner member 4E. In addition, this can morereliably prevent a case where one wire out of the adjacent wires for theinner coil 41 of the inner member 4E rides on the other wire, which canoccur while the guidewire 1 is used.

FIG. 6 is an enlarged longitudinal cross-sectional view of an innermember included in a guidewire (sixth exemplary embodiment) according tothe disclosure herein.

Hereinafter, the sixth exemplary embodiment of the guidewire accordingto the disclosure will be described with reference to the drawing.However, points different from those in the above-described embodimentswill be mainly described, and description of the same points will beomitted.

The sixth embodiment is the same as the first embodiment except that ahorizontal cross-sectional shape of a wire for the inner member isdifferent.

As illustrated in FIG. 6, in the guidewire 1 of the sixth embodiment,the horizontal cross-sectional shape of the wire for the inner coil 41which configures an inner member 4F is a flat shape. In the illustratedconfiguration, the shape is a rectangular shape, and the longitudinaldirection thereof is the same as the longitudinal direction of the wire.In addition, the rectangular shape may be configured so that each cornerportion 411 has a right angle, respectively. However, it is preferablethat the corner portion be rounded as illustrated in FIG. 6.

Since the horizontal cross-sectional shape of the wire for the innercoil 41 has a rectangular shape, the vicinity of the proximal endportion of the first wire 2 whose rigidity is lower than that of thesecond wire 3 is likely to be largely deformed with respect to thebending stress. However, by covering the vicinity of the proximal endportion with the inner member 4F, it is possible to further suppressexcessive curving-deformation in the vicinity of the proximal endportion of the first wire 2 whose rigidity is lower than that of thesecond wire 3. In addition, the inner member 4F is relatively thin, andaccordingly, contributes to a decrease in the diameter of the guidewire1. The thickness of the wire for the inner coil 41 depends on thediameter of the wire of the outer coil 52. For example, when thediameter of the wire of the outer coil 52 is 40 μm to 50 μm, thethickness is preferably 10 μm to 40 μm, and is more preferably 20 μm to30 μm.

FIG. 7 is an enlarged longitudinal cross-sectional view of an innermember included in a guidewire (seventh exemplary embodiment) accordingto the disclosure herein.

Hereinafter, the seventh exemplary embodiment of the guidewire accordingto the disclosure will be described with reference to the drawing.However, points different from those in the above-described embodimentswill be mainly described, and description of the same points will beomitted.

The seventh embodiment is the same as the first embodiment except that ahorizontal cross-sectional shape of a wire for the inner member isdifferent.

As illustrated in FIG. 7, in the guidewire 1 of the seventh embodiment,the horizontal cross-sectional shape of the wire for the inner coil 41which forms an inner member 4G is a flat shape. In the illustratedconfiguration, the shape is an elliptical shape, and the longitudinaldirection thereof is the same as the longitudinal direction of the wire.

Since the horizontal cross-sectional shape of the wire for the innercoil 41 is the elliptical shape, the vicinity of the proximal endportion of the first wire 2 whose rigidity is lower than that of thesecond wire 3 is likely to be largely deformed with respect to thebending stress. However, by covering the vicinity of the proximal endportion with the inner member 4G, it is possible to further suppressexcessive curving-deformation in the vicinity of the proximal endportion of the first wire 2 whose rigidity is lower than that of thesecond wire 3. In addition, the inner member 4G is relatively thin, andaccordingly, contributes to a decrease in the diameter of the guidewire1.

FIG. 8 is an enlarged longitudinal cross-sectional view of an innermember included in a guidewire (eighth exemplary embodiment) accordingto the disclosure herein.

Hereinafter, the eighth embodiment of the guidewire according to thedisclosure will be described with reference to the drawing. However,points different from those in the above-described embodiments will bemainly described, and description of the same points will be omitted.

The eighth embodiment is the same as the first embodiment except that ahorizontal cross-sectional shape of a wire for the inner member isdifferent.

As illustrated in FIG. 8, in the guidewire 1 of the eighth embodiment,the horizontal cross-sectional shape of the wire for the inner coil 41which forms an inner member 4H is a flat shape. In the illustratedconfiguration, the shape is a semicircular shape, and the longitudinaldirection thereof is the same as the longitudinal direction of the wire.

Since the horizontal cross-sectional shape of the wire for the innercoil 41 is the semicircular shape, the vicinity of the proximal endportion of the first wire 2 whose rigidity is lower than that of thesecond wire 3 is likely to be largely deformed with respect to thebending stress. However, by covering the vicinity of the proximal endportion with the inner member 4H, it is possible to further suppressexcessive curving-deformation in the vicinity of the proximal endportion of the first wire 2 whose rigidity is lower than that of thesecond wire 3. In addition, the inner member 4H is relatively thin, andaccordingly, contributes to a decrease in the diameter of the guidewire1.

In addition, in the wire for the inner coil 41, a plane 413 opposite toa curved surface 412 thereof faces the wire body 10. This allows theinner member 4H to be stably placed on the wire body 10.

The inner members 4F to 4H of the sixth to eighth exemplary embodimentshave an aspect in which the adjacent wires for the inner coil 41 are incontact with each other. However, the adjacent wires for the inner coil41 may have a gap therebetween.

FIG. 9 is a longitudinal cross-sectional view illustrating a ninthexemplary embodiment of a guidewire according to the disclosure herein,and is a side view of an inner member included in the guidewireillustrated in FIG. 9.

Hereinafter, the ninth embodiment of the guidewire according to thedisclosure will be described with reference to the drawing. However,points different from those in the above-described embodiments will bemainly described, and description of the same points will be omitted.

The ninth embodiment is the same as the first embodiment except that ashape of the inner member is different.

As illustrated in FIGS. 9 and 10, in the guidewire 1 of the ninthembodiment, an inner member 4I is formed by a pipe (tube). The innermember 4I (pipe) has multiple penetrating portions 461 which penetrate atube wall 46 (refer to FIG. 10). The penetrating portions 461 are formedas multiple slots along a circumferential direction of the inner member4I. Positions of the adjacent slots are different from one another.

This inner element 4I has the sufficient flexibility, and thus, it ispossible to relieve the stress in the joint portion 14. Accordingly, asdescribed above, the operability is improved in the guidewire 1.

Note that, each of the penetrating portions 461 has a slot shape in theconfiguration illustrated in FIG. 10. However, without being limitedthereto, for example, the shape may be a circular shape, a spiral shape,an elongated notch (slit) shape, or a strip-like notch shape.

The configuration of the inner member 4I illustrated in FIG. 10 can alsobe used as the outer member 5 in the above-described embodiments.

Hitherto, the guidewire of the disclosure herein has been described withreference to the illustrated exemplary embodiments. However, the presentinvention is not limited thereto. The portions constituting theguidewire each can be substituted by any desired configuration which candemonstrate the same function. In addition, any desired constitutingelement may be added thereto.

In addition, the guidewire of the present invention may be formed bycombining any two or more desired configurations (features) within theabove-described exemplary embodiments.

In addition, the inner peripheral portion of the inner member is spacedapart from the outer peripheral portion of the wire body in theembodiments. However, without being limited thereto, the innerperipheral portion of the inner member may be in contact with the outerperipheral portion of the wire body.

In addition, the inner member is cantilevered in the above-describedembodiments. However, without being limited thereto, the inner membermay be supported in both ends. For example, when the inner member issupported in both ends, the torque transmission performance of the guidewire is improved.

In addition, a resin layer may be interposed between the outer memberand the inner member.

A guidewire of the disclosure herein includes a wire body that has afirst wire which is arranged on a distal end side and a second wirewhich is arranged on a proximal end side of the first wire and is formedof a material whose rigidity is higher than that of a constitutingmaterial of the first wire, and in which a proximal end surface of thefirst wire and a distal end surface of the second wire are joined toeach other so as to form a joint portion, an outer member that isarranged on an outer peripheral side of the wire body, that forms atubular shape which covers the wire body at least from a distal endportion of the first wire to the joint portion, and that hasflexibility, and an inner member that is arranged between an outerperipheral portion of the wire body and an inner peripheral portion ofthe outer member, and that covers the joint portion. The inner member isan inner coil formed by winding a wire for the inner member into a coilshape.

Therefore, when the guidewire is used, a torque acting around an axisthereof, a pushing force acting from a proximal end side thereof, and apressing force acting from a curved blood vessel (force which bends theguidewire) are all applied to the guidewire. In this case, stress isgenerated in a joined portion formed by a first wire and a second wirebeing joined to each other. However, according to the disclosure here,the stress is reliably relieved by the inner member. This can reliablyprevent a problem in which the guidewire is unintentionally bent in thejoint portion or is broken in the joint portion, while the guidewire isused (operated). Accordingly, the guidewire is excellent in operabilitysuch as torque transmission performance, pushing performance, and kinkresistance, for example. Therefore, the guidewire disclosed here hasindustrial applicability.

The detailed description above describes a guide wire disclosed by wayof example. The invention is not limited, however, to the preciseembodiments and variations described. Various changes, modifications andequivalents can be effected by one skilled in the art without departingfrom the spirit and scope of the invention as defined in theaccompanying claims. It is expressly intended that all such changes,modifications and equivalents which fall within the scope of the claimsare embraced by the claims.

What is claimed is:
 1. A guidewire comprising: a wire body that has afirst wire arranged on a distal end side and a second wire arranged on aproximal end side of the first wire, the second wire being formed of amaterial whose rigidity is higher than that of a material forming thefirst wire, and a proximal-most end surface of the first wire and adistal-most end surface of the second wire being joined to each other soas to form a joint portion; an outer member arranged on an outerperipheral side of the wire body and forming a tubular shape whichcovers the wire body at least from a distal end portion of the firstwire to the joint portion, the outer member having flexibility; and aninner member having a distal end and a proximal end, the inner memberbeing arranged between an outer peripheral portion of the wire body andan inner peripheral portion of the outer member, and covering the jointportion; wherein the inner member is an inner coil formed by winding awire for the inner member into a coil shape; and wherein a distal end ofthe inner member is not fixed to the wire body.
 2. The guidewireaccording to claim 1, wherein the inner coil has a distal end portionand a proximal end portion, and at least any one of the distal endportion and the proximal end portion is stretchable.
 3. The guidewireaccording to claim 1, wherein the joint portion has an outer diameterwhich is the same as an outer diameter of a proximal end of the firstwire on a distal end side and an outer diameter of a distal end of thesecond wire on a proximal end side, respectively, and wherein an innerdiameter of the inner coil is larger than an outer diameter of the jointportion.
 4. The guidewire according to claim 1, wherein a horizontalcross-sectional shape of the wire for the inner member has a circularshape or a flat shape.
 5. The guidewire according to claim 4, whereinthe wire for the inner member has a rectangular shape.
 6. The guidewireaccording to claim 4, wherein the wire for the inner member has anelliptical shape.
 7. The guidewire according to claim 4, wherein thewire for the inner member has a semicircular shape.
 8. The guidewireaccording to claim 1, wherein the outer member is configured to have afirst outer coil located on a distal end side and formed by winding awire for a first outer member into a coil shape and a second outer coilconnected to a proximal end side of the first outer coil and formed bywinding a wire for a second outer member into a coil shape; and whereinthe wire for the inner member is thinnest wire among the wire for thefirst outer member, the wire for the second outer member, and the wirefor the inner member.
 9. The guidewire according to claim 8, wherein awinding direction of the wire forming the inner coil is the same as awinding direction of a wire forming the first outer coil and the secondouter coil.
 10. The guidewire according to claim 8, wherein a windingdirection of the wire forming the inner coil is opposite to a windingdirection of the wire forming the second outer coil.
 11. The guidewireaccording to claim 1, wherein the inner member relieves stress generatedin the joint portion when the guidewire is used.
 12. The guidewireaccording to claim 1, wherein the inner coil forming the inner member iscoarsely wound such that adjacent windings of the inner coil are spacedapart.
 13. The guidewire according to claim 1, wherein the outer memberis fixed to the wire body via a fixing material disposed at a locationwhere the inner member is arranged between the wire body and the outermember.
 14. The guidewire according to claim 13, wherein the innermember protrudes distally from the fixing material.
 15. The guidewireaccording to claim 13, wherein the distal end of the inner member isspaced proximally from the fixing material.
 16. The guidewire accordingto claim 15, wherein the proximal end of the inner member contacts thesecond wire.
 17. The guidewire according to claim 1, wherein the innermember includes only one fixing portion.
 18. The guidewire according toclaim 17, wherein the fixing portion of the inner member is disposeddistally relative to the joint portion of the wire body.
 19. Theguidewire according to claim 14, wherein a protruding amount of theprotruding portion from the fixing material is 1% to 34% of an overalllength of the inner member.